Device for calculating sheet number in a sheet feeder and method for calculating the same

Abstract

A device for calculating the number of recording papers on an automatic sheet feeder, including a sheet thickness detector, generating a sheet thickness value, and a sheet pile thickness detector, generating a sheet pile thickness value, which the processor divides by the sheet thickness value, generates and displays the number of the recording papers on the sheet feeder.

What is claimed is: 
     
       1. A sheet feeding apparatus, comprising: a sheet thickness sensor comprising a first light sensor emitting a light beam along a path of conveyance of passing sheets drawn from a stack of a plurality of cut sheets of recording stock, with each of said sheets of said recording stock exhibiting a sheet thickness and said stack exhibiting a stack thickness, and a second light sensor responsive to said light beam, generating a sheet thickness value corresponding to variation in reflection of said light beam attributable to passage of the individual ones of said sheets;   a stack thickness sensor generating a stack thickness value corresponding to said stack thickness; and   a processor generating a sheet number indicative of a number of said cut sheets of said recording stock in said stack in dependence upon said sheet thickness value and said stack thickness value.   
     
     
       2. The sheet feeding apparatus as recited in claim 1, said stack thickness sensor comprising: a resistor having a resistance; and   a lever contacting said resistor at a position that varies with the stack thickness   and varies said resistance as a function of said stack thickness.   
     
     
       3. The sheet feeding apparatus as recited in claim 2, wherein the sheets are maintained vertically by said lever. 
     
     
       4. The sheet feeding apparatus as recited in claim 2, said blade being biased against the sheets. 
     
     
       5. The sheet feeding apparatus as recited in claim 1, further comprised of said sheet thickness sensor including a guide having a surface reflecting said light beam. 
     
     
       6. The sheet feeding apparatus as recited in claim 5, said guide rotating, responsive to a sheet drawn from a stack of sheets, defining a rotation proportional to the sheet thickness. 
     
     
       7. The sheet feeding apparatus as recited in claim 5, said surface retreating from said light source, responsive to a sheet drawn from a stack of sheets, defining a distance proportional to the sheet thickness. 
     
     
       8. The sheet feeding apparatus as recited in claim 5, further comprised of a roller mounted on said guide. 
     
     
       9. The sheet feeding apparatus as recited in claim 8, said roller contacting the sheet drawn from a stack of sheets. 
     
     
       10. The sheet feeding apparatus as recited in claim 9, said roller being biased against the sheet. 
     
     
       11. A sheet feeding apparatus, drawing sheets of recording stock from a stack of sheets, wherein each sheet has a sheet thickness and the stack has a stack thickness, comprising: a sheet thickness sensor generating a sheet thickness value corresponding to the sheet thickness;   a stack thickness sensor generating a stack thickness value corresponding to the stack thickness; and   a processor receiving said sheet thickness value and said stack thickness value and generating a sheet number;   said stack thickness sensor comprising: a resistor having a resistance; and   a lever contacting said resistor at a position that varies with the stack thickness and varies said resistance as a function of said stack thickness.     
     
     
       12. The sheet feeding apparatus as recited in claim 11, wherein the sheets are maintained vertically by said lever. 
     
     
       13. The sheet feeding apparatus as recited in claim 11, said lever being biased against the sheets. 
     
     
       14. A method for determining a number of sheets in a sheet feeder comprising the steps of: gauging a stack of sheets having a stack thickness;   generating a sheet stack thickness value based on the stack thickness;   gauging a sheet having a sheet thickness;   generating a sheet thickness value based on the sheet thickness; and   generating a sheet number indicative of a number of sheets within the stack, in dependence upon said stack thickness value and said sheet thickness value.   
     
     
       15. The method as recited in claim 14, further comprised of performing said step of gauging a stack by using a stack thickness sensor comprising: a resistor having a resistance; and   a wiper contacting said resistor at a position and varying said position with the stack thickness;   wherein said resistance varies with said stack thickness.   
     
     
       16. The method as recited in claim 15, wherein the sheets are maintained vertically by said wiper. 
     
     
       17. The method as recited in claim 15, said wiper being biased against the sheets. 
     
     
       18. The method as recited in claim 14, said step of gauging a stack of sheets including a sheet thickness sensor comprising: a light source producing a light beam having an intensity; and   a light sensor, responsive to said light source, generating a value proportional to said intensity.   
     
     
       19. The method as recited in claim 18, said sheet thickness sensor including a guide having a surface reflecting said light beam. 
     
     
       20. The method as recited in claim 19, said guide rotating, responsive to a sheet drawn from a stack of sheets, defining a rotation proportional to the sheet thickness. 
     
     
       21. The method as recited in claim 19, said surface retreating from said light source, responsive to a sheet drawn from a stack of sheets, defining a distance proportional to the sheet thickness. 
     
     
       22. The method as recited in claim 19, including a roller mounted on said guide. 
     
     
       23. The method as recited in claim 22, said roller contacting the sheet drawn from a stack of sheets. 
     
     
       24. The method as recited in claim 23, said roller being biased against the sheet. 
     
     
       25. A sheet number sensing apparatus, comprising: a frame of an automatic sheet feeder;   a feed roller installed in said frame;   a sheet support installed in said frame, a cut sheet being loadable between said feed roller and said sheet support;   a sensor responding to said sheet support by generating a stack thickness signal;   a processor responding to said stack thickness signal and a sheet thickness value stored in said processor by generating a sheet number indicative of a number of sheets within a stack formed by a plurality of the cut sheet.   
     
     
       26. The apparatus of claim 25, further comprised of said sensor including a lever contacting said sheet support, installed in said frame. 
     
     
       27. The apparatus of claim 25, further comprised of said stack thickness signal varying in synchronization with a movement of said sheet support. 
     
     
       28. A sheet feeding apparatus, comprising: a sheet thickness sensor comprising a first sensor along a path of conveyance of sheets drawn from a stack of a plurality of cut sheets of recording stock, with each of said sheets of said recording stock exhibiting a sheet thickness and said stack exhibiting a stack thickness, and a second sensor responsive to said signal, generating a sheet thickness value corresponding to variation of said signal attributable to passage of the individual ones of the sheets;   a stack thickness sensor generating a stack thickness value corresponding to said stack thickness; and   a processor generating a sheet number indicative of a number of said sheets of said recording stock in the stack in dependence upon said sheet thickness value and said stack thickness value.